Honda CRF50F 2017 Owner's Manual page 23

Modifications
We strongly advise you not to remove any
original equipment or modify your
motorcycle in any way that would change its
design or operation. Such changes could
seriously impair your motorcycle's
handling, stability and braking, making it
unsafe to ride.
Because safety, vehicle movement, and
clearance must be taken into consideration,
you must consult your tyre maker or Honda
dealer before changing your tyre model
type.
Removing or modifying your exhaust
system (such as the spark arresters or
mufflers) or other equipment can also make
your motorcycle illegal.
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